1. Field of the Invention
The present invention relates to a time setting system, an imaging device, a video-device, and a time setting method that allow a date and a time to be easily set for an internal clock of a device.
2. Description of the Related Art
A portable video camera has internal calendar and clock with which a date and a time at which an image was captured can be stamped on the image when it is recorded. Since this clock uses a crystal oscillator that has high accuracy and a small error, after the current date and time have been set for the video camera, even if it has left without adjustment, the error of the clock of the video camera is small. However, although the error of the clock is small, as time elapses, the error gradually increases. In addition, while the video camera is operating, since the internal temperature of its housing rises, the oscillation frequency of the crystal oscillator varies due to changed temperature characteristics of the crystal oscillator. As a result, time of the clock deviates. In addition, as the voltage of a backup battery of the clock varies, the oscillation frequency varies and thereby time of the clock deviates.
The frequency and environment in which the video camera is used depend on the user. One user may use the video camera only several times in a year. Another professional user may use the video camera 24 hours, 365 days. Thus, the temperature, voltage, and so forth of the video camera vary when it is used. Against such various environments in which the video camera is used, it is very difficult to maintain the accuracy of the internal clock in a high level.
In the past, when the date and time of the internal clock deviated, the user manually set the date and time for the clock according to information displayed on a monitor disposed on the video camera. Related art of which a time is set for a video camera with keys according to a menu is described in Patent Document 1.
[Patent Document 1] Japanese Patent Application Unexamined Publication No. HEI 6-86107
Next, with reference to FIG. 1A and FIG. 1B, an example of a method of setting a date and a time that was used in the related art will be described in brief. FIG. 1A shows an appearance of an example of a portable video camera 200. Disposed on for example an outer side surface of the portable video camera 200 is an operation section 220 that has keys with which settings and so forth of the video camera 200 are performed. A monitor 210 displays captured images, recoded images, and setting information.
When a date and a time are set for the portable video camera 200, for example with a key disposed on the operation section 220, a setting menu is displayed on the monitor 210. A date and time setting menu is selected from the setting menu. FIG. 1B shows the date and time setting screen selected from the setting menu and displayed on the monitor 210. The monitor 210 displays a screen on which items “YEAR”, “MONTH”, “DAY”, “HOUR”, and “MINUTE” are set.
When the value of each item is changed, with keys, each item for example “MONTH” is selected and a value of the selected item is selected. In such a manner, each of the other items, which are “DAY”, “HOUR”, and “MINUTE” of the date and time of the internal clock of the portable video camera 200 is selected and then a value of the selected item is selected. After each item is selected and the value of the selected item is selected, “OK” at the lower right of the display is pressed. As a result, the date and the time can be set for the internal clock of the portable video camera 200.